bug#47781: 28.0.50; (window-list-1 nil t) returns nil when minibuffer is inactive

[martin rudalics]

> I read from the docstring of the function
>> MINIBUF t means consider the minibuffer window even if the minibuffer is not 
active
>
> However, with emacs -Q
> and the minibuffer inactive
>
> (window-list-1 nil t)
> ;; => nil
>
> I think this is related to this build since I cannot reproduce with emacs 
26.1 (in this case it returns the list of windows, minibuffer included, as 
expected).
>
>
> In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.5, 
cairo version 1.16.0)
> of 2021-02-09 built on debian-10-gccemacs

This is likely broken since a change in candidate_window_p from last
year, see commit 2ecbf4cfae7bd504fbdca28e1e51ee2574fe5d12 (waiting for
Gregory's confirmation).  Since `window_list_1' is consulted in quite a
number of places, the behavior of Emacs might be slightly unpredictable
in this area.

martin